Derivation and Validation of a Modified Short Form of the Stroke Impact Scale

Background: the stroke impact scale (sis) is a stroke-specific,quality of life measure recommended for research and clinical practice. completion rates are suboptimal and could relate to test burden. we derived and validated a short form sis (sf-sis). methods and results: we examined data from the virtual international stroke trial archive,generating derivation and validation populations. we derived an sf-sis by selecting 1 item per domain of sis,choosing items most highly correlated with total domain score. our validation described agreement of sf-sis with original sis and the sis-16 and correlation with barthel index,modified rankin scale,national institutes of health stroke scale,and euro-qol 5 dimensions visual analog scales. we assessed discriminative validity (associations between sf-sis and factors known to influence outcome [age,physiological parameters,and comorbidity]). we assessed face validity and acceptability by sharing the sf-sis with a focus group of stroke survivors and multidisciplinary stroke healthcare staff. from 5549 acute study patients (mean age 68.5 [sd 13] years,mean sis 64 [sd 32]) and 332 rehabilitation patients (mean age 65.7 [sd 11] years,mean sis 61 [sd 11]),we derived an 8-item sf-sis that demonstrated good agreement with original sis and good correlation with our chosen functional and quality of life measures (all ρ>0.70,p<0.0001). significant associations were seen with our chosen predictors of stroke outcome in the acute group (p<0.0001). the focus group agreed with the choice of items for sf-sis across 7 of 8 domains. conclusions: using multiple,complementary methods,we have derived an sf-sis and demonstrated content,convergent,and discriminant validity. this shortened sis should allow collection of robust quality of life data with less associated test burden. © 2016 the authors. published on behalf of the american heart association,inc.,by wiley blackwell.